The purpose of this project is to identify the gene and the mutation responsible for the predisposition to MEN1, an autosomal dominant disease linked to markers in the 11q13 region. Although the proximal flanking marker has been identified to be D11S480, several distal flanking markers have been reported. Cosmid, P1 or PAC clones were isolated for these and other markers in this region. These clones were used to establish the order of the markers by interphase FISH, thereby defining the smallest MEN1 interval (based on the linkage studies). In addition, using the same clones, we have isolated and characterized 6 new microsatellite markers within this minimal interval. These markers will be used in LOH(loss of heterozygosity) studies to identify the minimal deleted region in MEN1 tumors. YAC, PAC and P1 clones were isolated using STSs and probes generated for the MEN1 interval. Additional STSs were generated by sequencing the ends of nearly every clone, and those STSs mapped to 11q13 were used in the STS-content analysis of the clones and for screening the YAC/PAC/P1 libraries. The overlapping clones cover the entire MEN1 interval (D11S427 to D11S913) except for one region. The sequences generated from the end clones were subjected to BLAST analysis of the EST database which resulted in the identification of 9 known/unknown genes. Efforts will be made to identify all the transcripts in the interval and search for the mutations.